F-projectors and F-covering subgroups of finite groups

详细

Given a nonempty set ω of primes and a nonempty class F of groups, we define the F^ω- projector and F^ω-covering subgroup of a finite group and study their properties (existence, invariance under certain homomorphisms, conjugacy, and embedding). We extend the results of Gasch¨utz, Schunck, Erickson, and others.